It was chilly. It was early. But, more than four dozen people turned out to run and cycle in the Iron Horse Duathlon on Sunday morning.

“I wanted to do it with my friends but my friends didn’t show up,” said 9-year-old Brent Lee.

It wouldn’t have been so bad, but the three pals had signed up for a relay.

With both his parents, Alex and Monica Lee, beaming at him with pride for not having bailed on the race, the Bridgeport Elementary School student described how he got up at 5:30 a.m., then ran, cycled and ran again in the event sponsored by H2OpenPlus.

“It was tiring,” he said.

Lee joined 50 other competitors — more than half of them children — at the Iron Horse Trailhead off Magic Mountain Parkway, who gathered at the start/finish line near the historic 1898 railroad trestle bridge, just east of Interstate 5.

For Michael and Dawn Snowden, equally proud parents of three competing daughters, the event was a chance to get the family doing something healthy.

“To get up at 6 o’clock and brave the cold, they did it,” Michael Snowden said at the finish line.

“I’m really proud of them.”

The Snowdens clustered under the finish line banner and hugged their girls — Cassidy, 4, and her older sisters, both of North Park Elementary School, Caitlin, 10 and Cameron, 8.

Participants signed up for one of three events that got underway at 8 a.m., including: